This is an observational study of HIV-infected subjects who are CMV-seropositive and who have not had clinical symptoms of CMV disease at study entry to 1) define relationships between HIV load and risk of CMV disease; CMV load and the risk of developing CMV disease; and CMV load and HIV load. 2) To establish threshold CMV and HIV load values in peripheral blood fractions that are associated with development of CMV end-organ disease. 3) To define the natural history of CMV infaction in the context of highly active antiretroviral therapy (HAART).